In a small bowl, mix mustard with brown sugar and soy sauce. Reserve ¼ cup, cover with plastic wrap and refrigerate.

Add chicken wings into a large resealable bag. Add the marinade, seal securely and marinate for at least 2 hours, turning occasionally to let the marinade soak through wings on all sides. Preferably, leave the wings in the fridge to marinate overnight.

While preheating oven to 375°F/190°C/Gas Mark 5, remove wings from the bag (discard the marinade); arrange wings on a baking sheet.

Bake for 30 minutes; then start basting with the marinade you reserved every 10 minutes. Cook, basting, for 30 minutes more. Serve with fav sauce.